Chemistry questions and answers

Chemistry Questions and Answers

Learn more about the properties, composition, and structure of substances (elements and compounds) with these Chemistry questions and answers. This Test can be used by students preparing for Chemistry in JAMB, WAEC, NECO or Post UTME.

1,136.

N2O4(g)→ 2NO2(g)

In the endothermic reaction above, more products formed will be favored by

A.

A constant values

B.

an increase in pressure

C.

a decrease pressure

D.

a decrease volume

Correct answer is C

A decrease in pressure will result in the breaking or splitting of a larger molecule into a simpler ones. Options A, B, D are not in conformance to the reaction

1,137.

what is the pH of 0.00lmoldm3 solution of sodium hydroxide

A.

14

B.

13

C.

12

D.

11

Correct answer is D

[H+][OH−] = 10 − 4
[H+] =10 − 14 ÷ [OH+]
=10 −14 ÷ (1 × 10 − 3) = 10 − 11
pH = − log10[H+ ]
= − log10[10 − 11] = − 1 × −11
log10[10 − 11] = 1
= − 1 × 11 × 1
= − 11

1,138.

Which of the following compounds can be represented by the molecular formula C2 H6O?

A.

propanal

B.

ethanol

C.

methanoic acid

D.

glucose

Correct answer is B

Ethanol has the molecular formula C2H6O. Option A, C, D are not because their molecular are not different

1,139.

If glucose is heated with concentrated tetraoxosulphate(vi)acid, it will be dehydrated to?

A.

carbon

B.

carbon(iv)oxide

C.

ethane

D.

ethanol

Correct answer is A

Carbon concentration of 4 will not give a precipitate heating. Option B,C,D will not be dehydrated

1,140.

The substance that is used in the steel industry for the removal of carbon. Sulphur and phosphorus impurities from pig iron is

A.

oxygen

B.

chlorine

C.

nitrogen

D.

hydrogen

Correct answer is A

Oxygen is a substance that is used to remove impurities from pig iron. Options B, C, D will be effective in removing impurities positive]